condition mean min max ZT0-3 8.748069 8.748069 8.748069 ZT4-7 9.3835735 9.3835735 9.3835735 ZT8-11 8.3643825 8.3643825 8.3643825 ZT12-15 8.925518499999999 8.925518499999999 8.925518499999999 ZT16-19 8.748069 8.748069 8.748069 ZT20-23 8.623169 8.623169 8.623169